Arroworthy Microfiber Nap Jumbo Cage Roller Refill Twin Pack - 4 Inch & 6.5 Inch Trade quality microfiber roller sleeves for use with both oil and water-based paints. 3/8" Nap (9.63cm) Smooth and semi-smooth surfaces Ideal for plaster, wood & metal 9/16" Nap (14.29) Semi smooth and semi-rough surfaces Ideal for plaster, wood & metal that is slightly uneven or with light texture